231 research outputs found

    Effects of a nickel reactor liner and other reaction variables during supercritical water reformation of glycerin

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    The non-catalytic reformation of glycerin using supercritical water was conducted in a 400-mL tubular reactor constructed of Haynesʼ Alloy 230. The evaluated parameters for this thesis include water-to-glycerin molar ratios ranging from 3 to 24 and reactor temperatures ranging from 500⁰C to 700⁰C. In addition, experiments were performed using the Haynes\u27 Alloy 230 reactor both without a liner and with a Nickel 201 liner. Space time was maintained at approximately 100 seconds and the reactor pressure was kept constant at 24.1 MPa. The resultant effect on product gas composition and carbon gasification was determined. The product gases consisted of a mixture of hydrogen, carbon monoxide, carbon dioxide, methane and ethane. It was found that the greatest gas yields of hydrogen were produced at higher temperatures using more dilute glycerin solutions. Increasing the water-to-glycerin ratio and increasing temperature, up to approximately 13.5 and 600⁰C respectively, increased the extent of carbon gasification. Once these values were reached, 100% carbon gasification percentages were achieved. The reactor liner made of nickel was found to have a positive catalytic effect on both the reformation and water gas shift reaction. The experiments conducted with the liners produced higher carbon dioxide and hydrogen yields. The greatest hydrogen and carbon dioxide yields were obtained at 24 water-to-glycerin ratio and a temperature of700⁰C using a reactor liner. In this thesis, the effects of water-to-glycerin ratios, temperature, and a reactor liner upon supercritical water reformation of glycerin are revealed based on the experimental data --Abstract, page iii

    Theorizing Development of Parasocial Engagement

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    The article proposes a theoretical model of the development of parasocial relationships (PSRs) building on Knapp’s model of relationship development. Through synthesis of research across disciplines, the model conceptualizes the relational goals and parasocial interactions (PSIs) specific to the PSR. The model identifies variables that predict engagement at that level, describes the stage’s outcomes/effects, and considers the utility of existing measures to assess these stages. The conceptualization of PSRs as a dynamic process rather than intensity of a monolithic experience offers new directions worthy of empirical examination

    Death and Communal Mass-Mourning: Vin Diesel and the Remembrance of Paul Walker

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    This article examines Vin Diesel’s use of his public Facebook Page to mourn the loss of his friend and co-actor Paul Walker in the period from 2013-2015. It discusses how Vin Diesel performed his grief and how his mourning process was communally reflected and repeated by both Vin Diesel and Walker fans, who used Vin Diesel’s page to share and verbalise their own feelings of loss in a both public and safe space. An analysis of Vin Diesel’s own status updates and 1800 comments reacting to three popular status updates related to the death of Paul Walk posted over the course of more than a year show that commentary was used to make condolences to both Vin Diesel and Walker’s familes and to affectively express the users’ immediate feelings, both verbally and through the use of emojis. However, over time, both the form and intensity of expression of both Vin Diesel and his followers changed, pointing to the need to further study celebrity mourning processes on social media over extended periods of time

    The geometry of the magnetic field in the central molecular zone measured by PILOT

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    We present the first far infrared (FIR) dust emission polarization map covering the full extent of Milky Way’s central molecular zone (CMZ). The data, obtained with the PILOT balloon-borne experiment, covers the Galactic center region − 2° < ℓ < 2°, − 4° < b < 3° at a wavelength of 240 μm and an angular resolution of 2.2′. From our measured dust polarization angles, we infer a magnetic field orientation projected onto the plane of the sky (POS) that is remarkably ordered over the full extent of the CMZ, with an average tilt angle of ≃22° clockwise with respect to the Galactic plane. Our results confirm previous claims that the field traced by dust polarized emission is oriented nearly orthogonally to the field traced by GHz radio synchrotron emission in the Galactic center region. The observed field structure is globally compatible with the latest Planck polarization data at 353 and 217 GHz. Upon subtraction of the extended emission in our data, the mean field orientation that we obtain shows good agreement with the mean field orientation measured at higher angular resolution by the JCMT within the 20 and 50 km s−1 molecular clouds. We find no evidence that the magnetic field orientation is related to the 100 pc twisted ring structure within the CMZ. The low polarization fraction in the Galactic center region measured with Planck at 353 GHz combined with a highly ordered projected field orientation is unusual. This feature actually extends to the whole inner Galactic plane. We propose that it could be caused by the increased number of turbulent cells for the long lines of sight towards the inner Galactic plane or to dust properties specific to the inner regions of the Galaxy. Assuming equipartition between magnetic pressure and ram pressure, we obtain magnetic field strength estimates of the order of 1 mG for several CMZ molecular clouds

    Operational experience and commissioning of the Belle II vertex detector

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    Belle II Vertex Detector Performance

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    The Belle II experiment at the SuperKEKB accelerator (KEK, Tsukuba, Japan) collected its first e+e− collision data in the spring 2019. The aim of accumulating a 50 times larger data sample than Belle at KEKB, a first generation B-Factory, presents substantial challenges to both the collider and the detector, requiring not only state-of-the-art hardware, but also modern software algorithms for tracking and alignment. The broad physics program requires excellent performance of the vertex detector, which is composed of two layers of DEPFET pixels and four layers of double sided-strip sensors. In this contribution, an overview of the vertex detector of Belle II and our methods to ensure its optimal performance, are described, and the first results and experiences from the first physics run are presented

    Concept design of low frequency telescope for CMB B-mode polarization satellite LiteBIRD

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    LiteBIRD has been selected as JAXA’s strategic large mission in the 2020s, to observe the cosmic microwave background (CMB) B-mode polarization over the full sky at large angular scales. The challenges of LiteBIRD are the wide field-of-view (FoV) and broadband capabilities of millimeter-wave polarization measurements, which are derived from the system requirements. The possible paths of stray light increase with a wider FoV and the far sidelobe knowledge of -56 dB is a challenging optical requirement. A crossed-Dragone configuration was chosen for the low frequency telescope (LFT : 34–161 GHz), one of LiteBIRD’s onboard telescopes. It has a wide field-of-view (18° x 9°) with an aperture of 400 mm in diameter, corresponding to an angular resolution of about 30 arcminutes around 100 GHz. The focal ratio f/3.0 and the crossing angle of the optical axes of 90◦ are chosen after an extensive study of the stray light. The primary and secondary reflectors have rectangular shapes with serrations to reduce the diffraction pattern from the edges of the mirrors. The reflectors and structure are made of aluminum to proportionally contract from warm down to the operating temperature at 5 K. A 1/4 scaled model of the LFT has been developed to validate the wide field-of-view design and to demonstrate the reduced far sidelobes. A polarization modulation unit (PMU), realized with a half-wave plate (HWP) is placed in front of the aperture stop, the entrance pupil of this system. A large focal plane with approximately 1000 AlMn TES detectors and frequency multiplexing SQUID amplifiers is cooled to 100 mK. The lens and sinuous antennas have broadband capability. Performance specifications of the LFT and an outline of the proposed verification plan are presented
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